1. Field of the Invention
The present invention relates generally to the operation of graphical displays, and more particularly to the interface between a graphical display and a processor.
2. Related Art
Processing systems typically include a processor connected to a display through a display interface. Often, such processors contain graphics subsystems that directly handle the transfer of information, such as image data and control signals, between the processor and the connected display via the display interface. Multi-mode displays are capable of receiving image data signals in different formats, and displaying images in response to these differently-formatted signals. Image data signals are often categorized as being either digital or analog. There are many different industry standards that define various digital and analog image data signal formats.
Certain industry standards provide mechanisms that allow a display to transmit information across a display interface to an attached processor. This information indicates an image data signal format that the display supports. Once this information is received, the attached processor is able to determine the appropriate signal format in which to send image data to the connected display.
Unfortunately, these existing standards do not enable a multi-mode display to indicate its entire set of supported image data signal formats. That is, these standards only allow a multi-mode display to indicate to the processor one image data signal format at a given time.
Accordingly, a disadvantage of these existing standards involves situations where a particular processor supports some, but not all of the image data signal formats that a multi-mode display can support. For example, if a display indicates to a processor a signal format that the processor does not support, the processor will be unable to send image data signals to the display, even though the processor may support other signal formats that are within the attached display's capabilities.
It is generally recognized that displays must comply with industry-endorsed standards to achieve market acceptance. If a display does not comply with such standards, then it will not necessarily inter-operate with processors and graphics subsystems that are prevalent in the marketplace. Accordingly, there is a need for multi-mode displays that comply with industry standards and indicate to attached processors a mutually supportable display data signal format without excessive user interaction and undue delay.